Following the creation of inner-shell vacancy in an atom, the cascade of radiative and nonradiative transitions takes place. It can be analysed employing the final charge distribution of ions, the electron and characteristic emission spectra. The development of the experimental and theoretical investigation of cascades is shortly reviewed. The main attention is paid to the description of a cascade using the global characteristics of spectra, especially in the cases of transitions between close-lying and overlapping configurations. Some applications of the global characteristics method are given.